Detection of viable cells of Ralstonia solanacearum in soil
A method to detect viable cells of Ralstonia solanacearum (EPPO A2 quarantine pest) in soil has been developed in Japan. It combines the use of a semiselective medium (PCCG) and a PCR technique with specific primers. During these studies, 92 strains of soil bacteria were isolated from soil samples of 39 different fields in Honshu (JP). These fields, where tomato or aubergine had been grown, were known to be infected by R. solanacearum, and usually biovar 4 had been identified in infected plants. Out of these 92 strains, 12 were confirmed as R. solanacearum by biochemical and pathogenicity tests, and were specifically and efficiently (sensitivity threshold 102cfu/g soil) detected by this new method (PCCG followed by PCR). The authors noted that this method is rather rapid, as results can be obtained 3 days after soil sampling has been performed. Colonies can be observed on the semiselective medium after 48;h (incubation at 30°C) and readily tested by PCR.
Sources
Ito, S.; Ushijima, Y.; Fujii, T.; Tanaka, S.; Kameya-Iwaki, M.; Yoshiwara, S.; Kishi, F. (1998) Detection of viable cells of Ralstonia solanacearum in soil using a semiselective medium and a PCR technique.
Journal of Phytopathology, 146(8-9), 379-384.